Basic Human Biology

Cell Biology

Introduction to the human cell

The human cell is the basic unit of our being. Every complex organism, including humans, consists of coordinated systems working together to achieve...

Basic cytoskeleton proteins

Cytoskeletal proteins make up the cytoskeleton of a cell, which is the basic structural framework providing the cell a shape.

Structure and function of cytoplasm

The cytoplasm is the cytosol of the human cell - the cell substance in the interior of the cell. Humans are eukaryotes, meaning that their c...

Gene expression explained

Gene expression is the process by which proteins are made. Proteins carry out almost all of the essential processes of life.

DNA repair mechanisms

Deoxyribonucleic acid (DNA) is the genetic material of human cells. Changes in the DNA can disrupt cell function and result in disease. Cells contain their own mechanism for correcting this damage.

Endocytosis

The process of bringing something into a cell without it passing through the cell membrane via transport proteins.

Exocytosis

A process by which cells expel something, generally large particles that cannot pass through the cell membrane.

The Respiratory System

The respiratory system

Every cell and tissue of our bodies requires oxygen for its functions and produces carbon dioxide as waste. The respiratory system is responsible for this gas exchange.

Structure and function of the lungs

The lungs are part of the lower respiratory tract and are responsible for gas exchange.

Lung volumes and capacities explained

The lungs bring in oxygen and release carbon dioxide, providing the essential elements of life. The capacity of the lungs to exchange these gases is dependent on a number of factors.

Explanation of the mechanism of breathing

Breathing is a necessary mechanism in the human body. A breath occurs in two parts, inhalation (or inspiration) and exhalation (or expiration).

An overview of muscles in the neck

The neck muscles are responsible for head movement, head posture, swallowing (pharyngeal) and speaking (laryngeal), and are even integrated with...

Skeletal System

The skeletal system

The skeletal system, known more fondly as the skeleton, is made up of bones connected via cartilage and ligaments at joints.

Difference between ligaments and tendons

Ligaments and tendons are both connective tissues in the body, and they are both made of stacked bundles of collagen fibrils. The difference betwe...

The Different Types of Human Skeletal Joints

The joints are where two bones meet, but not all convey movement.

Human Skeletal Movement - Synovial Joints

The synovial joints allow bones to move in varying ways by holding and cushioning the ends of the bones.

Anatomy and physiology of the cervical spine

The cervical spine consists of the first seven vertebrae of the spine (C1-C7), starting at the base of the skull.

An overview of the five areas of the spine

The human spine is made up of 33 bones called vertebrae. However, not all of these bones are the same.

An overview of the bones in the cranium

Twenty-two bones make up the human skull.

Integumentary system

The integumentary system: Structure and function

The integumentary system includes the largest organ in the human body the skin. The system also includes the projections from the skin, the hair and nail follicles, and receptors.

Understanding skin, its roles and functions

To understand the function of the skin, one first has to know that the skin is made of layers.

What are skin tags?

Skin tags are actually very common though the name may seem unfamiliar. Known medically as acrochordons (or fibroepithelial polyp, cutaneous papil...

Melanocytes

Melanocytes are the pigment cells of the human body. These specialized cells determine what color the hair and skin are and contribute to eye color.

The Urinary Tract

The urinary system in human anatomy

The urinary system normally consists of two kidneys, a urinary bladder, two ureters, and a urethra (the urinary tract).

Renal anatomy and physiology

The kidneys are bean shaped organs in the abdominal cavity that are part of the urinary tract. The organs are held in place by connective tissue...

Human kidney structures

The kidneys are made of intricate webs of blood vessels and drainage canals for filtering wastes...

How the kidneys work

The kidneys maintain the pH, ion, and fluid balance of the blood. Humans usually have two of these bean-shaped organs in the abdominal cavity. To ...

Digestive System

The human gastrointestinal system

The gastrointestinal system, or GI tract, digests the food and other substances humans consume. In this process, it absorbs nutrients and water th...

The digestive system

The digestive system is also known as the gastrointestinal (GI) tract and is responsible for the digestion of food and absorption of nutrients and...

Structure and function of the stomach

The human stomach is a major organ of the gastrointestinal tract and found in the upper left quadrant of the abdomen. This organ system is involve...

Enzymes and secretions in the small intestine

The small intestine is a long tube-like network connecting the stomach and large intestine. This organ plays a role in both digestion and absorption.

Overview of types of cells in the nervous system

The nervous system contains two types of cells: neurons and neuroglia. Neurons are the basic nerve cell, specialized to carry electrical signals t...

The structure and function of neurons

Neurons are nerve cells, making up the functional core of the peripheral and central nervous systems.

The anatomy of the brain

The anatomy of the human brain is as complex as its function.

Brain structures that play a role in the fear response

The fear response is a complex cascade of chemical and electrical signaling triggered by the autonomic nervous system, the involuntary part of the nervous system.

The cranial nerves described

The cranial nerves are the 12 major nerves running into the brain from the brainstem, or originating from the brain itself.

The Tongue

The chemoreceptors of the tongue

Each human tongue contains an average of roughly 10,000 chemoreceptors. These microscopic hair-like nerve endings, called microvilli, are encapsul...

The sense of taste: Different tastes picked up by the human tongue

Taste is the sensing of flavor in food and other material that is ingested. Taste is possible because chemicals stimulate receptors on the tongue...

The Eyes

Introduction to the structure of the eye

The structure of the eye is conducive to its function. The function, as we know of course, is to see. Sight is the transmission of light signals th..., Alicia M Prater PhD

Basic functions of the human eye

The basic function of the human eye is to see. Other functions involving the accessory structures and secretions of the eye prevent foreign particl..., Alicia M Prater PhD

How vision works

A person sees through the process known as vision or sight. Sight works much like a camera. Vision is achieved using a refractory system that focus..., Alicia M Prater PhD

The Ears

The structure of the ear

The structure of the human ear consists of three anatomical sections - the inner ear, middle ear, and outer ear.

Anatomy and parts of the inner ear

The ear is one of the most complicated anatomical structures in the human body. It functions in two different body systems, the auditory (hearing)...

Anatomy and physiology of the cochlea

The cochlea is the main structure of the human auditory system. It is not actually an organ itself, but a bony structure in the inner ear that con...

Immune and lymphatic systems

Mucins explained

To put it simply, mucins are large extracellular glycoproteins and the main proteins found in mucus. Mucus plays a role in the immune system.

Function of the spleen

The spleen is a small organ in the abdominal cavity that is considered to be part of the lymphatic system, which also includes the lymph nodes.

Endocrine and Reproductive Systems

Endocrine glands of the human body

The human body has a complex chemical messenger system enabled by the endocrine system. The major components of this system, the endocrine glands,...

Function and importance of the thyroid gland

The thyroid gland is a butterfly shaped gland in the throat (see a picture). The thyroid uses the mineral iodine to produce hormones that are invo...

Structure and function of the female prostate

The female prostate is better known as the Skene's gland, though the colloquial term was accepted for descriptive anatomic use in 2001.

The human reproductive system

The reproductive system consists of internal and external sex organs and glands necessary for sexual reproduction.